That seems odd as the battery was charging ok just duscharging within a few hours, even left on standby
I know a little about the phones and, perhaps, can comment a bit more.
The "main PBA" (printed circuit board assembly) is the primary board that houses the phone's processor, memory, and other critical components. The "sub PBA" is a smaller board that connects to the main board and helps manage other functions like the camera, speakers, and sensors. As for the "CTC," this could refer to a component called the "charge time compensation IC," which helps regulate the battery charging process to ensure optimal performance and prevent damage to the battery.
I understand your confusion. It does seem strange that the repair technicians replaced the main PBA, sub PBA, and CTC.
It's possible that there were underlying issues with the circuit boards or other components that were causing the battery to drain faster than it should have been.
It's yet possible that there could have been other ways to repair the issue without replacing those components, for instance:
-Software issue: Sometimes, issues with battery life or charging can be caused by software problems, such as a misbehaving app or a software bug. In these cases, the technician may be able to diagnose the problem and fix it with a software update or by resetting the phone to its factory settings.
- Battery calibration issue: If the battery is not calibrated correctly, it may give inaccurate readings of its charge level, causing the phone to shut down or display incorrect battery life information. In this case, the technician can recalibrate the battery to ensure that it accurately reflects its charge level.
The solution depends on the specific diagnostic results and repair process set up in the service.
The technicians may have determined that replacing those parts was the best course of action to ensure that the issue was fully resolved.
Moreover, Samsung and authorized service centers typically prefer to be on the safe side and they use genuine Samsung parts to ensure high-quality repairs and long-term functionality of the phone.